JP3172491B2 - Digital camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital camera, and more particularly, to a digital camera for generating an image signal having a desired zoom magnification, for example.

[0002]

2. Description of the Related Art In a conventional digital camera of this type,
In order to generate a zoom image signal having a desired zoom magnification from a captured image signal, the image signal is temporarily stored in a field memory, and then the image signal is subjected to zoom processing using a line memory, an adder, a multiplier, or the like. Had been given.

[0003]

However, in such a conventional technique, circuits such as a field memory, a line memory, an adder, and a multiplier are required for the zoom processing, and thus there is a problem that the circuit configuration becomes complicated. Was. Therefore, a main object of the present invention is to provide a digital camera capable of generating an image signal having a desired zoom magnification with a simple circuit configuration.

[0004]

SUMMARY OF THE INVENTION The present invention relates to a photographing means.
Based on the image signal of the first number of horizontal pixels output from the
An image signal having a second horizontal pixel number smaller than the horizontal pixel number is generated.
Digital camera, the first zoom magnification is set.
When specified, the thinning processing is performed on the image signal of the first horizontal pixel number.
And outputs an image signal of the second number of horizontal pixels.
When the magnification is set, the first horizontal image is not
Thinning-out means for outputting a prime image signal, second horizontal pixel number
Reduce the capacity corresponding to the smaller number of third horizontal pixels
And temporarily stores the image signal output from the thinning means.
Buffer that temporarily holds the image signal of the third horizontal pixel number
Each time the image signal is written to the buffer,
Reading means for reading a signal from a buffer;
When the zoom factor is set, the second horizontal pixel number
The reading means is activated during one period, and the second zoom magnification is set.
Read in the second period related to the second horizontal pixel number when
Providing read control means for activating the output means.
A digital camera.

[0005]

The thinning means operates when the first zoom magnification is set.
The image signal of the first horizontal pixel number is subjected to the thinning-out process, and the second
An image signal with the number of flat pixels is output, and the second zoom magnification is set.
Image signal of the first horizontal pixel number without thinning
Is output. The buffer is smaller than the second horizontal pixel number.
It has at least a capacity corresponding to the third horizontal pixel number,
And temporarily holds the image signal output from the means. Reading
The extraction means outputs the image signal of the third horizontal pixel number to the buffer.
Buffers the image signal of the third pixel number every time data is written
Read from. Here, the read means is read control.
Controlled by the means and the readout means is activated
The interval differs depending on the zoom magnification. That is, the first zoom magnification
When the rate is set, the first horizontal pixel number related to the first
Activated during the period, but when the second zoom magnification is set
Is activated during a second period related to the second number of horizontal pixels.
You. Thereby, the first zoom magnification and the second zoom magnification
When any of the ratios is set, the image of the first horizontal pixel number
An image signal of a second horizontal pixel number is generated based on the signal;
You.

[0006]

According to the present invention, the thinning means and the reading means are provided.
The desired zoom magnification can be obtained simply by controlling the operation of the projection means.
Since image signals are generated, the circuit configuration can be simplified.
Become. The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, a digital camera 10 of this embodiment has a CCD imager 1 having effective pixels of "640" and "480" in the horizontal and vertical directions, respectively.
2 inclusive. A primary color filter (not shown) is mounted on the front surface of the CCD imager 12, and a light image of a subject is irradiated on the CCD imager 12 through the primary color filter.

The CCD imager 12 is driven by a timing signal output from a timing generator (TG) 13 in response to power-on. That is, when the operator turns on the power, the system controller 50
Sets the camera mode in the CPU 42 through the interrupt terminal 42a. Then, the CPU 42 activates the signal generator (SG) 15 and the signal generator (S
G) 15 outputs the horizontal synchronization signal shown in FIGS. 6A and 7A and the vertical synchronization signal not shown. TG
The 13 generates a timing signal based on the horizontal synchronization signal and the vertical synchronization signal, and drives the CCD imager 12 in a progressive scan system.

A camera signal output from the CCD imager 12 is a primary color signal in which each pixel has one of R, G and B primary color components. The output camera signal is C
The DS / AGC circuit 14 performs well-known noise removal and level adjustment, and then converts the digital data into camera data, which is a digital signal, by an A / D converter 16 operating at a clock rate of 12 MHz. The signal processing circuit 18 performs YUV conversion on the camera data output from the A / D converter 16 at a ratio of 4: 2: 2 to generate image data, that is, YUV data.

The signal processing circuit 18 also operates according to the horizontal synchronizing signal and the vertical synchronizing signal from the SG 15 as shown in FIG.
The above signal processing is executed in accordance with the clock of 12 MHz shown in FIG. As a result, the Y data shown in FIG. 6C and the UV data shown in FIG. 6D, or the Y data shown in FIG. 7C and the UV data shown in FIG.
Data is output simultaneously from the two signal paths. The Y data, U data and V data are all 1
8 bits per pixel.

When the power is turned on, the system controller 50 sets the standard camera mode. As a result, a moving image having a VGA resolution is displayed on the monitor 40. That is, in the standard camera mode, 640 pixels × 480 zoomed by 1 ×.
The moving image of the line is displayed on the monitor 40. Here, when the operator operates the zoom button 44 , the system controller 50 sets a zoom mode, whereby a moving image having a resolution of QVGA is displayed on the monitor 40. The zoom mode includes a 1 × zoom mode and a 2 × zoom mode. In the 1 × zoom mode, a moving image of 320 pixels × 240 lines thinned out every other pixel is cut out from the center of the screen in the 2 × zoom mode. The moving image of 320 pixels × 240 lines is displayed on the monitor 40.
In order to display a moving image according to the mode as described above, the image data output from the signal processing circuit 18 is processed as follows.

In the standard camera mode and the 2 × zoom mode, the enable signal EN0 shown in FIG.
3 and serially connected D-FF circuit 2
0a to 20d. As a result, the D-FF circuits 20a to 20d are always activated and latch input data in response to a 12 MHz clock. That is, the Y data sequentially output from the signal processing circuit 18 is latched for each pixel as shown in FIG.
At the same time. To the D-FF circuit 24, four consecutive pixels in the horizontal direction, that is, 32-bit Y data are simultaneously input.

On the other hand, an enable signal EN1 shown in FIG. 6F is input to the D-FF circuits 22a to 22d connected serially. The D-FF circuits 22a to 22d are also always activated and latch input data in response to a 12 MHz clock. The U data and V data output from the signal processing circuit 18 are alternately switched every eight bits as shown in FIG. Each data amount of U data and V data is Y by 4: 2: 2 conversion.
Since the data is １ ／ of the data, U data and V data for two pixels are output from the other signal path while Y data for four pixels is output from one signal path. Such UV data for two pixels is supplied to the D-FF circuits 22a to 22a.
It is simultaneously input to the D-FF circuit 26 via 2d.

The D-FF circuits 24 and 26 are shown in FIG.
As shown in (G), input data is latched in response to an enable signal EN2 which rises for one clock period every three clocks. As a result, 32-bit Y data and UV data are output from the D-FF circuits 24 and 26 at the timings of FIGS. 6 (H) and 6 (I). D-
Outputs of the FF circuits 24 and 26 are supplied to a switch SW1, and time-division multiplexed by a SW signal that changes every two clock periods as shown in FIG. Switch S
From W1, time-division multiplexed YUV data is output as shown in FIG. This YUV data is 640
It has a pixel x 480 line data amount and a transfer rate of 6
MHz.

On the other hand, in the 1 × zoom mode, FIG.
The enable signal EN0 shown in FIG.
The enable signal EN1 input to the FF circuits 20a to 20d and shown in FIG.
a to 22d, and an enable signal EN2 shown in FIG. 7G is input from the TG 13 to the D-FF circuits 24 and 26. The D-FF circuits 20a to 20d are activated intermittently every clock period, and the signal processing circuit 1
The Y data shown in FIG. 7C output from 8 is latched every other pixel. As a result, the Y data of four pixels thinned out every other pixel in the horizontal direction is output to the D-FF circuit 2.
4 are simultaneously input.

The D-FF circuits 22a to 22d are shown in FIG.
Are activated intermittently every two clock periods by an enable signal EN1 shown in FIG. Therefore, the signal processing circuit 1
The U data and V data shown in FIG. 7D output from 8 are also latched every other pixel. That is, since the U data and V data corresponding to one predetermined pixel are output over two clock periods, the U data and V data are latched every other pixel by the enable signal EN1 whose level changes every two clocks. . As a result, two pixels of UV that are thinned out every other pixel in the horizontal direction
Data is input to the D-FF circuit 26 at the same time.

The D-FF circuits 24 and 26 are shown in FIG.
The input data is latched in response to the enable signal EN2 shown in (G). The enable signal EN2 is at a high level for one clock period every seven clocks, thereby
Two-bit Y data and UV data are output from the D-FF circuits 24 and 26 at the timings of FIGS. 7 (H) and 7 (I). The SW signal changes every four clock periods as shown in FIG. 7 (J), and time-division multiplexed YUV data is output from the switch SW1 as shown in FIG. 7 (K). This YUV data is 320 pixels x 240
It has the data amount for the line and the transfer rate is 3 MHz.

As can be understood from the above description, the D-FF circuits 20a to 20d, 22a to 22d, 24 and 26, and the TG 13 constitute the thinning circuit 21. Such a thinning circuit 21 is activated / disabled by the CPU 42 according to the mode. Therefore, in the 1 × zoom mode, VGA resolution image data having a 1 × zoom magnification is generated.

The buffer 28 is constituted by a dual-port SRAM as shown in FIG. The memory area is divided into two banks, and the number of words in each bank is “32”
Where each word has a capacity of 32 bits. That is,
Each bank can store YUV data for 64 pixels.
The YUV data output from the switch SW1 is input to such a buffer 28.

The TG 13 supplies the address signal shown in FIG. 6 (L) and the bank switching signal shown in FIG. 6 (M) to the buffer 28 in the standard camera mode and the 2 × zoom mode to the buffer 28 in the 1 × zoom mode. ) And the bank switching signal shown in FIG. In either mode, the address signal and the bank switching signal are applied in synchronization with the YUV data. As a result, in the standard camera mode and the 2 × zoom mode, YUV data for 64 pixels continuous in the horizontal direction is written to any bank, and in the 1 × zoom mode, 64 pixels are thinned out every other pixel in the horizontal direction. Minutes of YUV data is written to any of the banks.
Y data is stored in the first 16 words of each bank.
Data is stored in the latter 16 words.

In the 1 × zoom mode, since pixel data is thinned out every other pixel, it takes twice as long to write 64 pixels as in the standard camera mode and the 2 × zoom mode. FIG. 2 shows an example of pixel data written to the buffer 28 in the standard camera mode and the 2 × zoom mode. YU of each bank
The V data is read by the memory control circuit 32 based on a read request output from the TG 13. The read request is shown in FIG. 6 (N) and FIG.
As can be seen from (N), it is generated in synchronization with the rise and fall of the bank switching signal. However, the read request is sent to the gate circuit 4 before the memory control circuit 32.
8 and gates any of the read requests depending on the mode. The memory control circuit 32 reads out image data from the buffer 28 only in response to the read request output from the gate circuit 48. The read pixel data is sent to the S via the buses 30 and 33.
The data is written to the DRAM 34.

In the standard camera mode, the gate signal is
As shown in (G), the level becomes high over one line period, and ten read requests shown in FIG. 8 (F) are input to the memory control circuit 32 during one line period.
The memory control circuit 32 reads out pixel data of 640 pixels from the buffer 28 during one line period, and
Write to. The gate circuit 48 outputs a gate signal shown in FIG. 8G for any line. In the standard camera mode, since the thinning circuit 21 is disabled,
All image data of 0 pixels × 480 lines is input to the memory control circuit 32 and written to the SDRAM 34.

Even in the 2 × zoom mode, the thinning circuit 21 is disabled, and image data of 640 pixels × 480 lines is sequentially written into the buffer 28. However, the gate signal in the 2 × zoom mode is at a high level only at the center of one line period as shown in FIG.
Only the central five of the ten read requests shown in (A) are input to the memory control circuit 32. For this reason, the memory control circuit 32 reads out pixel data of 320 pixels from the buffer 28 in one line period, and
Write 34. Even in the vertical direction, the gate circuit 64
Outputs the gate signal shown in FIG. 8A only in the central 240 lines. As a result, in the 2 × zoom mode, only image data of 320 pixels × 240 lines cut out from the center of the screen is written to the SDRAM 34.

In the 1 × zoom mode, the gate signal shown in FIG. 8E is output over all lines. Therefore, all the read requests generated by the TG 13 are input to the memory control circuit 32. However, pixel data written to the buffer 28 in the 1 × zoom mode is thinned out every other pixel, and only five read requests are output in one line period. Therefore, the image data written to the SDRAM 34 is pixel data of 320 × 240 lines thinned out every other pixel.

As can be seen from the above description, TG13,
Gate circuits 48 and the memory control circuit 32, a clipping circuit 49 to configure. Then, the CPU 42 activates / disables the cutout circuit 49 according to the mode. In addition,
In the standard camera mode, both the thinning circuit 21 and the cutout circuit 49 are disabled, but in the 1 × zoom mode, only the thinning circuit 21 is activated, and in the 2 × zoom mode, only the cutout circuit 49 is activated. That is, C
The PU 42 selectively activates the thinning circuit 21 and the cutout circuit 49 according to the zoom mode.

In the standard camera mode and the 2 × zoom mode, a read request is input at the timing shown in FIG. 9D, and in the 1 × zoom mode, a read request is input at the timing shown in FIG. 9A. The memory control circuit 32 responds to such a read request as shown in FIG. 9B or FIG.
An address signal is output at a rate of MHz, and YUV data is read from the buffer 28 as shown in FIG. 9 (C) or FIG. 9 (F). As described above, the memory control circuit 32
Image data is read at a rate of 4 MHz, and the reading speed is four times or eight times the writing speed of the image data to the buffer 28. In other words, image data is converted to SD
The period during which the buses 30 and 33 are occupied for writing to the RAM 34 is １ ／ or の of the entire period.

The memory control circuit 32 includes buses 30 and 3
During the period in which 3 is open, image data is read from the SDRAM 34 by the interlaced scan method and input to the NTSC encoder 38. The NTSC encoder 38
The input image data is encoded in the NTSC format, and a composite video signal obtained by the encoding is supplied to the monitor 40. As a result, a moving image corresponding to the mode is displayed on the screen. That is, in the standard camera mode, a 1 × moving image having the resolution of VGA is displayed, in the 1 × zoom mode, a 1 × moving image having the resolution of QVGA is displayed, and in the 2 × zoom mode, the moving image has the resolution of QVGA. Double moving images are displayed.

The TG 13 is configured as shown in FIG. The horizontal synchronization signal input from the SG 15 is input to reset terminals of an octal counter 13a, a hexadecimal counter 13h, and a binary counter 13k. That is, all of the counters 13a, 13h and 13k are reset by the horizontal synchronization signal. The octal counter 13a is
Incremented by the clock of MHz and "0"
A count value of any one of .about. "7" is output. The output count value is input to decoders 13b to 13g. The decoder 13b counts “0”, “2”,
When it takes "4" and "6", it outputs a high level signal, and the decoder 13c counts "3" and "7".
Output a high-level signal when The decoder 13d outputs a high level signal when the count value is "7", and the decoder 13e outputs a count value "0",
When "1", "4" and "5" are taken, a high level signal is output. Further, the decoder 13f outputs a high-level signal when the count value takes "2", "3", "6" and "7", and the decoder 13g provides a signal when the count value takes "4" to "7". To output a high level signal.

The CPU 42 operates the switch S according to the mode.
W2 to SW5 are controlled. That is, in the standard camera mode and the 2 × zoom mode, the switches SW2 to SW5
Are connected to the terminals S1 to S4, respectively, and the switches SW2 to SW5 are connected to the terminals S5 to S8 in the 1 × zoom mode, respectively. Therefore, the switches SW2 and S
W4 is connected to DC power supplies V1 and V2 in the standard camera mode and the 2 × zoom mode, respectively, and is connected to decoders 13b and 13e in the 1 × zoom mode, respectively. Also, switches SW3 and SW5
Are connected to the decoders 13c and 13f in the standard camera mode and the 2 × zoom mode, respectively, and are connected to the decoders 13d and 13g in the 1 × zoom mode, respectively.

The output of the switch SW2 is the enable signal E
N0, and the output of the switch SW3 becomes the enable signal E
N2. Further, the output of the switch SW4 becomes the enable signal EN1, and the output of the switch SW5 becomes the switch S
It becomes a SW signal for controlling W1. Hexadecimal counter 13h
Is incremented by the carry signal of the octal counter 13a, and the count value is determined by the decoders 13i and 13j.
Is input to The decoder 13i has a hexadecimal counter 13h
The decoder 13j outputs a high level signal when the count value of the hexadecimal counter 13h takes "15". That is, the decoder 13i outputs a high-level signal every 64 pixels, and the decoder 13j outputs
A high level signal is output for each pixel. Switch SW6
Is also controlled by the CPU 42. Switch SW
Reference numeral 6 is connected to the terminal S9 in the standard camera mode and the 2 × zoom mode, and connected to the terminal S10 in the 1 × zoom mode.

The output of the switch SW6 is a binary counter 1
3k clock terminal. Binary counter 13k
Is incremented every 64 pixels in the standard camera mode and the 2 × zoom mode, and is incremented every 128 pixels in the 1 × zoom mode. That is, the count value of the binary counter 13k switches between “0” and “1” every 64 or 128 pixels. The output of such a binary counter 13k becomes a bank switching signal. The output of the binary counter 13k is also input to the edge detection circuit 13m, which detects the rising edge and the falling edge of the bank switching signal. The output of such an edge detection circuit 13m is a read request.

The gate circuit 48 is configured as shown in FIG. The H counter 48a is incremented by a clock of 12 MHz and reset by a horizontal synchronizing signal. On the other hand, the V counter 48b is incremented by the horizontal synchronization signal and reset by the vertical synchronization signal. Therefore, the count value of the H counter 48a counts, for example, "0" to "779", and the V counter 4a
8b counts, for example, "0" to "559". H
The horizontal count value output from counter 48a is input to decoders 48c and 48d, and the vertical count value output from V counter 48b is output to decoders 48e and 4d.
8f.

On the other hand, the CPU 42 has predetermined numerical data.
H_E, H_S, V_EAnd V_STo the decoders 48a to 48f
Set to each. Numeric data H_SIs horizontal
Specify the rising position of the gate signal
_EDefines the fall position of the gate signal in the horizontal direction.
Set. Also, numerical data V_SIs the game in the vertical direction
The rising position of the signal_EIs hanging
Specifies the fall position of the gate signal in the vertical direction
You. Each numerical data H_S, H_E, V_SAnd V _E
Is the standard mode or 1x zoom mode and 2x zoom mode.
And between the code.

Each of the decoders 48c to 48f outputs a high-level signal only when the input count value matches the set numerical value. Outputs of the decoders 48c and 48d are input to a set terminal and a reset terminal of the RS-FF circuit 48g, and outputs of the decoders 48e and 48f are input to a set terminal and a reset terminal of the RS-FF circuit 48h. Accordingly, the output of the RS-FF circuit 48g rises when the horizontal count value matches the numerical data H _S, it falls when the horizontal count value matches the numerical data H _E. On the other hand, the output of the RS-FF circuit 48h rises when the vertical count value matches the numerical data V _S, it falls when the vertical count value matches the numerical data V _E. Such an RS-FF circuit 48
The outputs of g and 48h are ANDed by an AND circuit 48i to generate a gate signal.

The AND circuit 48j receives the output from the TG 13
Read request and output from the AND circuit 48i.
Receiving the input gate signal, the gate signal
A read request is issued to the memory control circuit 32 only when
Power. The CPU 42 supplies the file shown in FIG.
The process of the row diagram starts. First, in step S1, TG1
3 and gate circuit 48 in VGA 1 × mode, that is, normal
Operate in camera mode. Specifically, the switch shown in FIG.
Connect switches SW2 to SW5 to terminals S1 to S4 respectively
Then, the switch SW6 is connected to the terminal S9. FIG.
Numerical data is generated so that the gate signal shown in (G) is generated.
TA H_S, H_E, V _SAnd V_EIs the decoder 4 shown in FIG.
8c to 48f. As a result, the VGA
A 1 × moving image having a resolution is displayed on the monitor 40.

Next, the CPU 42 determines whether or not the zoom button 44 has been pressed in step S3. Here, "YE
If "S", the TG 13 and the gate circuit 48 are operated in the QVGA 1 × mode, ie, the 1 × zoom mode in step S5. At this time, the switches SW2 to SW5 are connected to the terminals S5 to S8, respectively, and the switch SW6 is connected to the terminal S10. are connected. Further, as the gate signal shown in FIG. 8 (E) is generated, numerical data H _S, H _E, the V _S and V _E is set to the decoder 48C～48f. Consequently, the QVGA 1x moving image with resolution on monitor 4
Displayed as 0.

Subsequently, the CPU 42 monitors the operation of the zoom button 44 and the zoom-off button 46 in steps S7 and S9, respectively. If the zoom button 44 is pressed again, the CPU 42 determines "YES" in step S7, and switches the TG13 gate circuit 48 to QV in step S11.
The operation is performed in the GA double mode, that is, the double zoom mode.
Therefore, the switches SW2 to SW5 are connected to the terminals S1 to S4, and the switch SW6 is connected to the terminal S9. Also, numerical data H _S so that the gate signal shown in FIG. 8 (C) is generated, H _E, V _S and V _E is the decoder 48c
４８48f. As a result, a double moving image having the resolution of QVGA is displayed on the monitor 40.

On the other hand, when the zoom-off button 46 is operated, the CPU 42 determines "YES" in the step S9, and returns the processing to the step S1. When the processing in step S11 is completed, the CPU 42 monitors the operation of the zoom button 44 and the zoom-off button 46 in steps S13 and S15, respectively. When the zoom button 44 is pressed, the CPU 42 determines "YES" in step S13 and returns to step S5. However, when the zoom off button 46 is pressed, the CPU 42 determines "YES" in step S15 and returns to step S1.

As described above, once the zoom button 44 is pressed, the resolution of the displayed moving image is set to QVGA, and each time the zoom button 44 is pressed, the zoom magnification becomes 1
It can be switched between double and double. Zoom off button 4
When 6 is pressed, the resolution of the display image returns to VGA. In this embodiment, the description has been made using the primary color filters in which R, G, and B are arranged in a mosaic pattern. However, _Ye , _Cy ,
It may be used complementary color filter M _g and G arranged in a mosaic pattern.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is an illustrative view showing a buffer;

FIG. 3 is a block diagram showing a part of a timing generator.

FIG. 4 is a block diagram showing a part of a gate circuit.

FIG. 5 is a flowchart showing a part of the operation of the CPU;

FIG. 6A is a waveform diagram showing a horizontal synchronization signal,
(B) is a waveform diagram showing a 12 MHz clock,
(C) is an illustrative view showing Y data, (D) is an illustrative view showing UV data, (E) to (G) are waveform diagrams showing enable signals, and (H) and (I) Is DF
FIG. 7 is an illustrative view showing an output of the F circuit, (J) is an illustrative view showing a SW signal, (K) is an illustrative view showing an output of the SW, and (L) is an illustrative view showing an address signal. ,
(M) is a waveform diagram showing a bank switching signal, and (N) is a waveform diagram showing a read request.

FIG. 7A is a waveform diagram showing a horizontal synchronization signal,
(B) is a waveform diagram showing a 12 MHz clock,
(C) is an illustrative view showing Y data, (D) is an illustrative view showing UV data, (E) to (G) are waveform diagrams showing enable signals, and (H) and (I) Is DF
FIG. 7 is an illustrative view showing an output of the F circuit, (J) is an illustrative view showing a SW signal, (K) is an illustrative view showing an output of the SW, and (L) is an illustrative view showing an address signal. ,
(M) is a waveform diagram showing a bank switching signal, and (N) is a waveform diagram showing a read request.

FIG. 8A is a waveform diagram showing a horizontal synchronization signal,
(B), (D) and (F) are waveform diagrams showing read requests, and (C), (E) and (G) are waveform diagrams showing gate signals.

FIGS. 9A and 9D are waveform diagrams showing a read request, FIGS. 9B and 9E are waveform diagrams showing an address signal, and FIGS. 9C and 9F show buffer outputs. It is a waveform diagram.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Digital camera 13 ... Timing generator 18 ... Signal processing circuit 28 ... Buffer 32 ... Memory control circuit 34 ... SDRAM 38 ... NTSC encoder 42 ... CPU

Continuation of the front page (56) References JP-A-5-268504 (JP, A) JP-A-5-37867 (JP, A) JP-A 1-254078 (JP, A) JP-A-54-72917 (JP) , A) JP-A-11-103436 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04N 5/228 H04N 9/74

Claims (5)

(57) [Claims] A first horizontal pixel number output from the photographing means;
A first horizontal pixel number smaller than the first horizontal pixel number based on the image signal;
For digital cameras that generate image signals with two horizontal pixels
When the first zoom magnification is set, the first horizontal pixel number
The image signal is subjected to a thinning-out process to obtain an image of the second horizontal pixel number.
Output an image signal, and when the second zoom magnification is set,
The image signal of the first horizontal pixel number is obtained without performing the thinning process.
Output thinning means, corresponding to a third horizontal pixel number smaller than the second horizontal pixel number
Having at least a capacity for
A buffer for temporarily holding the input image signal, and the image signal of the third horizontal pixel number is written into the buffer.
Each time the image signal of the third pixel number is stored in the buffer
Reading means for reading from the first zoom magnification;
When set before the first period related to the first horizontal pixel number
Activating the reading / writing means and setting the second zoom magnification
Before the second period associated with the second horizontal pixel number
A read control unit for activating the read / write unit is provided.
A digital camera, characterized in that : 2. The method according to claim 1, wherein the image signal of the third pixel number is supplied to the buffer
Request output method that outputs a read request each time data is written to
Further comprising a step, wherein the read control means sets the first zoom magnification.
The readout output during the first period when the
When the request is enabled and the second zoom magnification is set
The read request output in the second period
Enabled, the read means responds to the enabled read request
In response, the image signal of the third pixel number is output from the buffer.
2. The digital camera according to claim 1 , which reads out . 3. The thinning means includes: a plurality of registers for shifting the image signal of the first horizontal pixel number by a first predetermined number of pixels; and a plurality of registers for intermittently setting the plurality of registers when the first zoom magnification is set. in a register control means for activating, according to claim 1 or 2 digital camera according. 4. The image signal of the first horizontal pixel number includes a Y signal, a U signal and a V signal having different data amounts, and the plurality of registers shifts the Y signal by one pixel. 4. The digital camera according to claim 3, further comprising a register, and a plurality of second registers that shift the U signal and the V signal one pixel at a time and alternately. 5. The register control means according to claim 1, wherein
Said plurality of first register control means for intermittently activating every pixel period of the first register, and 2 pixels of the plurality of second register when said first zoom magnification is set when the magnification is set second Les intermittently activated for each period
5. The digital camera according to claim 4, further comprising a register control means.